Chronic schistosomiasis imported in France: A retrospective multicentre analysis of 532 patients, calling for international recommendations

Evaluation of molecular and serological testing for imported urogenital schistosomiasis screening in a referral tropical medicine centre in Barcelona, Spain

BACKGROUND

Schistosomiasis, a major neglected tropical disease, is caused by Schistosoma spp. It is estimated that more than 200 million people are affected worldwide, mostly in Africa. The gold standard diagnosis of urogenital schistosomiasis (UGS) is the microscopic visualisation of Schistosoma haematobium eggs in concentrated urine; however, its sensitivity is low. This study aimed to evaluate the effectiveness of molecular and serological testing for imported UGS screening in asymptomatic sub-Saharan migrants in a non-endemic setting.

METHODS

A retrospective cross-sectional study between November 2021 and December 2022 was conducted by collecting demographic, clinical and laboratory data from the medical records of migrants from endemic areas screened for UGS at the International Health Unit Vall d'Hebron-Drassanes, Barcelona, Spain. Urine samples were analysed by real-time PCR for S. haematobium DNA and by microscopy for egg detection. Serum samples were tested using a serological assay based on enzyme-linked immunosorbent assay (ELISA). UGS was confirmed by a positive result in real-time PCR and/or microscopy, while possible UGS was defined as a case with only a positive serological result.

RESULTS

A total of 604 patients were included in this study; 32 out of 604 (5.3%) urine samples were positive for S. haematobium by real-time PCR and/or microscopy examination (confirmed UGS cases). Schistosoma haematobium DNA was detected in 28/604 (4.6%) urine samples, while eggs were visualised in 24/604 (3.9%), with 12 discordant cases between both techniques. Real-time PCR demonstrated a sensitivity of 83.3%, a specificity of 98.6%, and a kappa value of 0.76. Serology was performed in 529/604 cases and exhibited lower specificity, 70.87% (kappa value 0.26). Other laboratory parameters such as leukocyturia, microhaematuria, eosinophilia and elevated IgE were significantly associated with UGS diagnosis.

CONCLUSIONS

Real-time PCR proved to be more sensitive than microscopy for diagnosing imported UGS in non-endemic settings, with minimal discordance between methods. The serological test exhibited very low specificity and high sensitivity rates, suggesting its usefulness as a screening test among high-risk populations in non-endemic settings.

Therapeutic response to an empirical praziquantel treatment in long-staying sub-Saharan African migrants with positive Schistosoma serology and chronic symptoms: A prospective cohort study in Spain

OBJECTIVES

Sub-Saharan African migrants may be experiencing imported schistosomiasis, which can evolve into chronic schistosomiasis. Positive response to empiric treatment with praziquantel may indicate the presence of persistent infection.

METHODS

We tested the response to praziquantel in a cohort of sub-Saharan African migrants with probable chronic schistosomiasis. The tests were administered at baseline and 6 and 12 months.

RESULTS

Of the 187 eligible participants, 149 completed the follow-up. Of these, 119 (79.9%) were males and 65 (43.6%) were from Senegal. The median age was 43 years (interquartile ranges 35-51 years) and their duration of residence in Europe was 17 years (interquartile ranges 12-21 years). The most prevalent clinical symptom was chronic abdominal pain (N = 96, 64.4%), pelvic pain in males (N = 55, 46.6%), and dysmenorrhea (N = 21; 70.0%) in females. We observed a significant decrease (P <0.001) in the number of signs and symptoms at 12 months, and 70.3% showed a total resolution of the symptoms and significant decreases in transaminase levels, eosinophilia, and abnormal glomerular filtration rates. The rates of clearance in positive enzyme-linked immunosorbent assay and immunochromatography tests were 54.7% and 24.3%.

CONCLUSION

The positive response to praziquantel suggests that chronic schistosomiasis is a prevalent condition among long-staying African migrants. These results need to be confirmed in randomized clinical trials.

Imported schistosomiasis in travelers: Experience from a referral tropical medicine unit in Barcelona, Spain

BACKGROUND

Acute schistosomiasis occurs most often in travelers to endemic regions. The aim of the study is to describe the epidemiological, clinical and parasitological characteristics of patients with schistosomiasis acquired during an international travel.

METHODS

Observational retrospective study including all travel-related schistosomiasis cases seen at the International Health Unit Vall d'Hebron-Drassanes (Barcelona, Spain) from 2009 to 2022. Diagnosis of schistosomiasis was defined by the presence of Schistosoma eggs in stools or urine or the positivity of a serological test. We collected demographic, epidemiological, clinical, parasitological, and therapeutic information.

RESULTS

917 cases of schistosomiasis were diagnosed, from whom 96 (10.5 %) were travel-related. Mean age of the patients was 34.9 years, and 53.1 % were women. Median duration of the travel was 72 days, and geographical areas where travelers had contact with fresh water were Africa (82.3 %), Asia (12.5 %), and South America (5.2 %). Twenty (20.8 %) patients reported having had some clinical symptom, being gastrointestinal symptoms the most frequent. Two patients developed the classical Katayama syndrome. In eleven (11.5 %) cases eggs were observed in urine or feces samples, and 85 (88.5 %) cases were diagnosed by a positive serology. Ninety-one (94.8 %) patients received treatment with praziquantel with different therapeutic schemes. The two patients with Katayama syndrome received concomitant treatment with corticosteroids.

CONCLUSIONS

Schistosomiasis in travelers represented 10 % of the overall schistosomiasis cases in our center. Increasing the awareness in the pre-travel advice and implementing specific screening in those travelers at risk (long travelers, contact with fresh water) could reduce the incidence and associated morbidity in this group.

Male genitourinary schistosomiasis-related symptoms among long-term Western African migrants in Spain: a prospective population-based screening study

BACKGROUND

Schistosomiasis is highly endemic in sub-Saharan Africa and frequently imported to Europe. Male urogenital manifestations are often neglected. We aimed to ascertain the prevalence of genitourinary clinical signs and symptoms among long-term African migrants in a non-endemic European country using a serology test.

METHODS

We carried out a prospective, community-based cross-sectional study of adult male migrants from sub-Saharan Africa living in Spain. Schistosoma serology tests and microscopic urine examinations were carried out, and clinical data were obtained from an electronic medical record search and a structured questionnaire.

RESULTS

We included 388 adult males, mean age 43.5 years [Standard Deviation (SD) = 12.0, range: 18-76]. The median time since migration to the European Union was 17 [Interquartile range (IQR): 11-21] years. The most frequent country of origin was Senegal (N = 179, 46.1%). Of the 338, 147 (37.6%) tested positive for Schistosoma. Parasite eggs were present in the urine of only 1.3%. Nine genitourinary clinical items were significantly associated with positive Schistosoma serology results: pelvic pain (45.2%; OR = 1.57, 95% CI: 1.0-2.4), pain on ejaculation (14.5%; OR = 1.85, 95% CI: 1.0-3.5), dyspareunia (12.4%; OR = 2.45, 95% CI: 1.2-5.2), erectile dysfunction (9.5%; OR = 3.10, 95% CI: 1.3-7.6), self-reported episodes of infertility (32.1%; OR = 1.69, 95% CI: 1.0-2.8), haematuria (55.2%; OR = 2.37, 95% CI: 1.5-3.6), dysuria (52.1%; OR = 2.01, 95% CI: 1.3-3.1), undiagnosed syndromic STIs (5.4%), and orchitis (20.7%; OR = 1.81, 95% CI: 1.0-3.1). Clinical signs tended to cluster.

CONCLUSIONS

Urogenital clinical signs and symptoms are prevalent among male African long-term migrants with a positive Schistosoma serology results. Genital involvement can be frequent even among those with long periods of non-residence in their sub-Saharan African countries of origin. Further research is needed to develop diagnostic tools and validate therapeutic approaches to chronic schistosomiasis.